1. Technical Field
The present invention relates to a liquid developer and an image forming apparatus, and in particular relates to a liquid developer and an image forming apparatus that can use the liquid developer.
2. Related Art
As a developer used for developing an electrostatic latent image formed on a latent image carrier, there is known a liquid developer. In the liquid developer, toner particles formed of a material containing a coloring agent such as a pigment or the like and a binder resin are dispersed into a carrier liquid (insulation liquid) having electric insulation properties.
Generally, a polyester resin is used as the binder resin of the toner particles. Such a polyester resin has high transparency. Therefore, in the case where the polyester resin is used as the binder resin, images obtained by using the liquid developer have superior color development and a high fixing characteristic.
In the meantime, a dispersant is added to a conventional liquid developer for the purpose of improving dispersibility of toner particles contained in the conventional liquid developer (one example of such a liquid developer is disclosed in JP-A-10-83100).
In the case where the dispersant is added to the conventional liquid developer, the dispersibility of the toner particles is improved. However, there is a problem in that a charge characteristic of the toner particles is lowered.
In order to solve the problem, a charge control agent such as a metallic soap and the like is added to the conventional liquid developer, thereby improving the charge characteristic thereof. However, in the case where the charge control agent such as the metallic soap and the like is used in the conventional liquid developer, an insulation property of the insulation liquid is lowered, so that a charge characteristic of the toner particles is lowered.
Therefore, it is difficult for a conventional liquid developer to improve both dispersibility and a charge characteristic of toner particles contained therein.